Pneumatic-valve mechanism



Nov. 8, 1927.

c. F. STODDARD PNEUMATIC VALVE NEQHANISM ma April 25. 1925 INVENTOR Patented Nov. 8, 1927.

.UNITEQD STAT-i815 T g F Fl C CHAR-LES F. s'ronnAnn, or new Yonx, n. Y., AEHSIGNOB, TO AMERICAN PIANO oom- PANY, OF NEW YORK, n. v. a coaronarion on NEW JERSEY.

PNEUMATIC-VALVE MECHANISM.

Application filed April 25, 1925. Serial N0. 25,725.

This invention relates to valve mechanisms particularly adapted for use in automatic musical instruments.

It is an object of this invention to provide a valve mechanism which shall operate noiselessly, but which shall at the same timebe of large capacity,--that is, it shall have the ability to pass relatively largequant1t1es of air with great rapidity. It is a further ob ject of the invention to provide means whereby said valve mechanism may be operated automatically from the tracker bar.

Other objects and advantages of the nvention will'appear hereinafter.

The single figure of the drawing illustrates semidiagrammatically a preferred embodiment of the invention selected for purposes of illustration.

Referring to the drawing the valve block 1 is provided with a chamber'2 having a conduit 8 leading to any suitable source of pneumatic exhaust. Located in the upper part of the chamber 2 is a cylindrical member 4 having a partition 5 arranged at the upper end thereof, said partition being provided with a plurality of perforations 6 to permit substantially free passage of air therethrough. Above the cylindrical member 4 and arranged to cover the partition 5 and the perforations 6 therein is a diaphragm 7, above which is a. diaphragm chamber 8.

The chamber 2 is connected by means of a duct 9 and connecting duct 10 with the exhaust chamber 11 of the inside valve 12. The diaphragm chamber'13 of this valve is also connected by means of duct 14 and the duct 9 to the chamber 2, a suitable bleed cup 15 being interposed in the duct 14; i

I The valve block 1 is also provided with a chamber 16 connected bymeans of a port 17 with a pneumatic 18 or other device, the operation of which is to be controlled by the valve mechanism. When the diaphragm? is seated, covering the perforations6 ofthe partition 5, passage of air between the chambers 16 and 2 is prevented, but when the diaphragm 7 is raised as hereinafter explained, air is drawnfrom the chamber 16 through the perforations 6, chamber 2, and conduit 3 to the source of exhaust.

v The diaphragm chamber 13.0f the valve 12 is provided with a duct 19 leading to a suitable opening of the usual tracker bar 19 of the instrument. If desired, a lock valve mechanism of any suitable construction such,

for instance, as illustrated in prior Patent No. 1,409,492, patented March 14, 1922, may be interposed between the duct 19 and the tracker bar in order that short perforations of a note sheetmay be employed to control I the 013812151011 of the valve mechanism.

In the normal course of operation, when the exhaust apparatus of the piano is started, the chamber 2 is subjected to exhaust. The chambers 11 and 13 of the valve-12 are also subjected to exhaust through the ducts 9, 10, and 14, and since the same degree of exhaust is maintained in both of the chambers 11 and 13, the valve 12 remains seated and atmosphere is'permitted to pass through the port 20 and duct 21 to the diaphragm chamber 8. The differential of pressure thus created between the atmosphere in diaphragm chamber 8 and the tension in chamber2 causes the diaphragm 7 to seattig'htly againstthe partition 5, sealing the perforations 6 to prevent the passage of air therethrough. 1

If under these conditions, a perforation in the note sheet crosses the tracker bar opening, atmosphere is admitted to the diaphragm chamber 13 through the tracker duct 19 more rapidly than it can be withdrawn through the bleed 15. A pressure differential is created thereby which causes the valve 12 to rise to close the port 20' to atmosphere and to open the port 22 to the exhaust chamber 11. The diaphragm chamber 8 is thereby subjected to exhaust through the duct 21 and pneumatic forces acting on the opposite sides of that part of the diaphragm 7 covering the partition 5 and the perforations 6 are equalized. The remainder of the diaphragm 7, however, is sub jected to exhaust on its upper side and to atmosphere from the chamber 16 on its lower side. This pressure differential immediately causes the edge of the diaphragm 7 to peel away from the partition 5 to'open the per-. forations 6, thus permitting air to be with drawn from the chamber 16. the partition 5 serving as a bearing surface for said diaphragm from which it may roll as it is influenced by pneumatic forces. As soon as the air has been exhausted from the chamber 16 sufficiently to equalize the pressures existing in the three chambers 2, 8 and 16, the diaphragm 7 returns to its seat under the influence of the light spring 7 This spring may be located in the chamber 8 and operates to return the diaphragm to its seat and I which is a diaphragm chamber 27 to hold it thereon except when raised under the influence of pneumatic forces as herein explained.

At the other end of the valve block 1 is arranged a cylindrical member 23 opening into the chamber 16 and having a partition 24 provided with a plurality of perforations 25 arranged at the upper end thereof simi:

larly to the parts 4, 5 and 6 previously described. Above the cylindrical member 23 and arranged to cover the partition 24 and perforations 25 is a diaphragm 26 above The diaphragm chamber communicates through the duct 28 with the valve chamber 29 of the inside valve 30. Chamber 31 beneath the valve 30 is connected by means of the duct 32 with the chamber 16, while chamber 33 is connected by means of the duct 34 with thechamber'controlled by the valve 12.

Whenever the valve 12 is raised, as previously described, the chamber33 of the valve 30 is subjected immediately to exhaust through the duct 34 while the chamber 31 is more gradually exhausted as the chamber 16 is exhausted due to the lifting of the diaphragm 7. Pressures are thus eventually equalized in chambers 31 and 33 but the valve 30 remains seated for prior to equalization the pressure in chamber 31 is greater than in chamber 33. So long as pressures in the chambers 31 and 33 are thus equalized,

valve 30 remains seated and is unaffected by the admission of atmosphere to the tracker I duct 19. Thus, under normal conditions, or durlngoperatlon of the diaphragm 7, valve 30 remains seated and atmosphere is admitted through the port 35 and duct 28to.

19 is closed to atmosphere, pressures in the chambers 11 and 13 are equalized and the and opening the port 36' to the tension which at the time exists in chamber 16. Thediaphragm chamber 27 is thereby exhausted and pressures actingon that part of the diaphragm covering the partition 24 and the perforations 25 are equalized. The remain ing portion of the diaphragm, however, is subjected to the pressure difierential between tension in the chamber 27 and atmosphere in the chamber 37 whereby the diaphragm 26 is caused to peel away from the partition 24 to permit atmosphere to enter through the perforations 25 to relieve the exhaust existing in chamber 16. As soon as the chamber 16 reaches atmospheric pressure, diaphragm 26 returns to its seat under the influence of spring 36. Valve 30 likewise returns to its seat by gravity since both of the chambers 31 and 33 are subjected to atmospheric pressure.

It will be observed that during the latter part of the operation, just described, it is the tension existing in the chamber 16 and pneumatic 18 which serves as the motive force to operate the valves to admit atmosphere to the chamber and pneumatic to re-' lieve the tensiontherein. Indeed itis the tension generated by the expansion of the pneumatic under the weight of the sticker 18 and attached parts which lifts the diaphragm 26 and keeps it lifted during the period during which atmosphereis being ad mitted to the chamber 16 and pneumatic 18.

The valve mechanism described may be useful in various parts of mechanisms for operating musical instruments automati-- cally. It has been found particularly useful for controlling the operation of pedal pneumatics where it is desired to collapsea pneumatic, of relatively large size with great rapidity. Heretofore it has been difficult to collapse such pneumatic rapidly without producing undesirable noises, for valves of the usual construction traveling from one seat to another, and having sufficient capacity to collapse the pneumatic rapidly were found to cause a slapping noise as they reached the opposite seat, and a lisping sound during transit from one seat to another. In the present construction it will be observed that due to the large capacity of the ports" formed by the perforations 6 and 25, an actuated pneumatic may collapse and expand with great rapidity. Due to the con struction and operation of the diaphragms controlling the ports, however, no undesirable noise is produced because the diaphragm is merely rolled off its seat and does not strike againstanother seat. In addition it returns to its seat under conditions wherein the pneumatic forces acting upon the diaphragm are substantially equalized and the diaphragm therefore in effect merely settles back onto the seat under the influence of its own weight and the force of the light springs 7 and 36. i

It will be understood that the invention may be variously modified and embodied within the scope of thesubjoined claims.

I claim as my invention: 7 i

1. In a pneumatic valve action, in combination, means for connection to a source of exhaust, means for connection to an actuated pneumatic. and means including a valve for controlling the application of exhaust to said pneumatic, said last-named means being adapted to cause said valve to open to collapse said pneumatic and to automatically close when said pneumatic is completely collapsed.

2. In a pneumatic "valve action, in combination, means for connection to a source of exhaust, means for connection to an actuated pneumatic, and means including a valve foricontrolling the application of exhaust to said pneumatic. said last-named means being adapted to cansesaid valve to open to collapse said pneumatic and to automatically close when said pneumatic is completely collapsed, and separate means for controlling the admission of atmosphere to said pneumatic to expand the same.

3. In a pneumatic valve action, in co1nbination, means for connection to a source of exhaust, means for connection to an actuated pneumatic, and means including a valve for controlling the application of exhaust to said pneumatic, said last-named means being adapted to cause said valve to open to collapse said pneumatic and to automatically close when said pneumatic is completely collapsed, separate means for controlling the admission of atmosphere to said pneumatic to expand the same, and means to control both of said means from a single tracker bar opening.

4. In a pneumatic valve action, in combination, means for connection to a source of exhaust, means for connection to an actuated pneumatic, means including a valve for controlling the application of exhaust to said pneumatic, said last-named means being adapted to cause said valve to open to collapse said pneumatic, and to automatically close when said pneumatic is completely collapsed, separate means including a valve for controlling the admission of atmosphere to said pneumatic to expand the same, said separate means being adapted to cause said included valve to open to admit atmosphere to expand said pneumatic and to automatically close when said pneumatic is completely expanded.

5. In a pneumatic valve action, in combination, means for connecting to a source of exhaust. means for connection to an actuated pneumatic, means including a valve for controlling the application of exhaust to said pneumatic, said last-named means being adapted to cause said valve to open to collapse said pneumatic, and to automatically close when said pneumatic is comp'letely collapsed, separate means including a valve for controlling the admission of atmosphere to said pneumatic to expand the same, said means being adapted to cause said valve to open to admit atmosphere to expand said pneumatic and to automatically close when said pneumatic is completely expanded, and means to control both of forces to become equalized when said pneumatic is completely collapsed whereby said valve closes automatically.

'7. In a valvemcchanism having a chamber connected with a source of exhaust and a second chamber to be exhausted, a valve actuated by the exhaust in said first chamher for controlling communication between said chambers whereby said second cham ber may be exhausted, and a second valve actuated by the residual tension in said second chamber for controlling communication between said chamber and atmosphere.

8. In' a pneumatic valve action, in combination, means for connection to a source of exhaust, meansfor connection to an actuated pneumatic. means including a valve actuated by said exhaust for controlling communication between said source of exhaust and said actuated pneumatic to collapse the same, and means including a second valve actuated by the exhaust generated by the expansion of said actuated pneumatic for controlling communication between said pneumatic and atmosphere.

9. In a pneumatic valve mechanism, in combination, a chamber connected with a source of exhaust, a second chamber to be exhausted, a third chamber, a valve for controlling communication between said first and second chambers, said valve being influenced by the pneumaticcondition existing in each of said chambers, and means including a valve for connecting said third chamber selectively to either atmosphere or to said first chamber.

10. In a pneumatic valve mechanism, in combination, a chamber connected with a source of exhaust, a second chamber to be exhausted, a third chamber, a diaphragm for controlling communication between said first and second chambers, said diaphragm being influenced by the pneumatic condition existing in each of said chambers, and means including a valve for connectingsaid third chamber selectively to either atmosphere or to said first chamber.

11. In a pneumatic valve mechanism, in combination, a chamber connected with a source of exhaust, a second chamber to be exhausted, a third chamber, a valve for controlling communication between said first and second chambers, said valve being infinenced by the pneumatic condition existing in each of said chambers, a tracker and tracker controlled means for connecting said third chamber selectively to either atmosphere or to said first chamber. a

12. In a pneumatic valve mechanism, in combination, a chamber connected with a source or exhaust, a second chamber to be exhausted, a third chamber, a diaphragm for controlling communication between said first and second chambers, said diaphragm being influenced by the pneumatic condition exist ing in each of said chambers, a tracker and tracker controlled means for connecting said third chamber selectively to either atmosphere or to said first chamber.

13. In a pneumatic valve mechanism, in

combination, a chamber connected with an actuated pneumatic, a second chamber having constant communication with atmosphere, a third chamber, a valve for control ling communication between said first and second chambers, said valve being influenced by the pneumatic condition existing in each of said chambers, and means including a valve for connecting said third chamber selectively to either atmosphere or to said first chamber.

14. In a pneumatic valve mechanism, in combination, a chamber connected vith an actuated pneumatic, a second chamber having constant communication with atmos-;.

April, 1925.

CHARLES F. STODDARD. 

